In Year 02 of this project, work will proceed along 3 lines: (1) The prototype of the ambulatory ventricular function monitor will be used to define changes in ventricular function in patients performing both sedentary activities and more vigorous upright exercise. In addition, the effect of drugs such as propranolol will be investigated. (2) A second ambulatory ventricular function monitoring device, made smaller, lighter and easier to carry will be constructed and tested. The second device will make practical the recording of data in patients undergoing vigorous stress, such as outdoor bicycling, or track events. (3) The software to automatically read and display the ventricular function curve, calculate numerical data such as ejection fraction and rate and define relative pulmonary blood volume continuously directly from the tapes will be improved.